In broad strokes, learning leads to better life outcomes just like brushing your teeth leads to better health outcomes, or any other example you may prefer. Brushing teeth is a chore so a child won't generally pick it up all by themselves without some nudging. If you don't do the nudging you're essentially letting a child be free, yes, but also willingly letting them end up worse off when they're too young to know any better. Learning is the same.
I don't think this argument is logically sound. Your eating habits are something that you personally have fairly high control over and can change with reasonable ease/effort. Society at large does not have the same characteristics and unless you have the means to live outside of society, you do have to deal with its realities.
Where did I say anything about living in the jungle?
The food choices having nothing to do with the jungle, but rather: regular, significant consumption of highly processed and most significantly sweetened foods. There were plenty of people in the world before the widespread adoption of sugar as cooking ingredient whose dental health would likely not have been improved by brushing, and they didn't live in "the jungle" but places like ... America, and Japan, and India and ... basically the entire planet.
